Arrangement for fitting a connection block in a cover

ABSTRACT

An arrangement in a telecommunications system for fitting a connection block in a cover so that a complete connecting unit is obtained, which can be connected to the front edge of a circuit board or in the back plane of a rack containing circuit boards. The arrangement is characterized by a cover formed so that a standardized connection block can be inserted into the cover guidance via guiding pins in the cover through the screw holes in the block normally used for screwing the block to the cover. The cover is provided with resilient end walls from which bosses project towards the interior of the cover. When the block is inserted into the cover, the end walls (3) deflect outwardly but reassume their original position when the block is engaged against stops in the cover, the projecting bosses engaging over the edges of the short ends of the connection block to lock the block to the cover.

FIELD OF THE INVENTION

The invention relates to an arrangement in a telecommunications systemfor fitting a connection block in a cover so that a complete connectingmeans is obtained which can be connected to the front edge of a circuitboard or in the back plane of a rack containing circuit boards.

DESCRIPTION OF PRIOR ART

In the Philips (Netherlands) data handbook from April 1978, Componentsand Materials, part 10, Connectors, there is shown under the cataloguenumber 433202625920 a typical example of how a connection block isattached in a cover by means of a plurality of screws. This is the mostusual way in the art of fitting a connection block into a cover, theblock being provided with rows of terminals to which wires are to beconnected. The cover thereby serves as a protection for the terminalsand wires.

In known embodiments, the problem occurs that the plastic material ofthe cover gradually cracks with repeated screwing or tightening withnuts in the material. A further problem is that when a completeconnector, i.e. connection block and cover, is fitted to a circuit boardand the cover needs to be removed, the whole connector must be removedso that the screws will be accessible, the electrical contact betweenboard and connector thus being broken.

SUMMARY OF THE INVENTION

The arrangement in accordance with the invention solves the problem bythe cover being so formed that a standardized connection block, e.g. ofthe type prescribed in DIN standard 41612 (IEC standard 130-14), ispushed into the cover and thereby obtains guiding by guiding pins in thecover through the screw holes in the block which are normally used forscrewed attachment. The cover is provided with resilient end walls onwhich projecting bosses directed towards the interior of the cover arearranged. When the block is pushed into the cover, said end walls firstdeflect outwardly but reassume their original position when the block ispressed against the bottom of the cover, the bosses then snapping inover the edges of the short ends of the block to lock it to the cover.With the aid of a tool the cover can easily be removed from the blockwithout interrupting the contact between the block and a connectedcircuit board. The advantages of the arrangement in accordance with theinvention in relation to known arrangements is that apart from astronger connector, there are also obtained large gains in time infitting and removing the connector, due to the technically simplesolution, which in turn give considerable economic advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail with the aid of anembodiment, while referring to the attached drawing, in which:

FIG. 1 is a front view of a cover in which a connection block can beinserted;

FIG. 2 is a side view of the cover, partly in section as taken alongline A--A in FIG. 1; and

FIG. 3 is a rear view of the cover.

PREFERRED EMBODIMENT

As is apparent from FIG. 1, a cover 1 (a plastic cover according to theexample) is provided with guiding pins 2 in the vicinity of each shortend, the task of these pins being to serve as guides for a connectionblock which is pressed into the cover. For said guidance the fact isutilized that the connection block is a standard block and the pinsguide the block in the through-holes which in known embodiments areutilized for screws. It is thus not the connection block itself which isthe inventive subject. It will be seen from the figure that both longsides of the cover 1 farthest out towards the end walls are providedwith slits 5 so that resilient end walls 3 are obtained. Each of the endwalls 3 is provided on the inside with a projecting boss 4 directedtowards the guiding pin 2. The bosses 4 are at a small distance from thepins 2. The task of the bosses is to snap in over the edges of the shortends of the block when the latter is fitted into the cover, therebylocking it in the cover. In conjunction with the respective guiding pin,the cover is provided with a stop projection formed as a wall 6 of givenheight. The walls 6 have the task of defining the bottom position forthe connection block in the cover. In the drawing, reference numerals 8and 9 refer respectively to the cable inlet of the cover and spaces forlocking means to circuit boards. These details are not pertinent to theinventive concept and are only illustrated to give a complete picture ofthe appearance of the cover, thereby to facilitate understanding theinvention.

FIG. 2 illustrates the cover from one side with the details in questionin cross-section. When a connection block is inserted into the cover,the guiding pins 2 are located in the screw holes of the block. The endsurfaces of the block simultaneously press against the projecting bosses4 disposed on the resilient end walls 3. These bosses are formed with aslope obliquely outwards towards the bottom of the cover so that theblock ends glide along the bosses and press the end walls 3 outwards.When the block comes into contact with the stop walls 6, the resilientend walls 3 deflect back and the bosses 4 snap in over the edge of therespective short end of the block to lock it to the cover.

From FIG. 3, which shows the cover from the rear, it will be apparentthat the cover is provided with openings 7 at the outer ends, throughwhich openings the cover can easily be released from the block by atool, without the block needing to be removed from the circuit board towhich it is connected.

The object of the arrangement in accordance with the invention is thusto provide a cover with greater strength than in known arrangements, andto achieve a cover from which gives better economy by enabling a simpleand rapid procedure when fitting and removing a block in the cover.

What we claim is:
 1. An arrangement in a telecommunications systemcomprising a cover, and a connection block fitted in said cover so thata complete connecting means is obtained, which can be connected to thefront edge of a circuit board or in the back plane of a rack containingcircuit boards, the connection block having holes normally utilized forreceiving screws to attach the cover to the block, said cover beingprovided with guiding pins guidably receiving the block in the cover viathe holes provided in the block normally used for screws, said coverincluding resilient end walls including bosses projecting inwardly intothe cover, said bosses snap-engaging edges of the connection block withthe block inserted into the cover, said cover further including a rearwall from which said resilient end walls project, and upper and lowerwalls connected to said end walls and rear wall, said cover beingprovided with slits to provide said end walls with the resiliencethereof to enable the bosses to snap-engage the edges of the connectionblock.
 2. The arrangement as claimed in claim 1 wherein said slits arearranged in pairs for each end wall, the slits in each pair being onopposite sides of the respective bosses on the associated end walls. 3.The arrangement as claimed in claim 2 wherein said slits are providedbetween the end walls and the upper and lower walls.
 4. The arrangementas claimed in claim 3 wherein said end walls have free edges extendingalong the length of the end walls and said bosses are spaced from thefree edges of the respective end walls.
 5. The arrangement as claimed inclaim 4 wherein said cover includes a further wall adjacent each endwall, said projections being located on the further walls, said pinsbeing located between respective end walls and further walls.
 6. Thearrangement as claimed in claim 1 wherein said cover is provided withholes which are externally accessible for removing the cover from theblock with a tool.
 7. The arrangement as claimed in claim 1 wherein rearwall has a length substantially greater than said end walls.
 8. Thearrangement as claimed in claim 1 wherein said bosses project intoadjacent spaced relation with said guiding pins to permit the block toengage over said pins and be inserted into the cover whereupon thebosses snap-engage the block.
 9. The arrangement as claimed in claim 1wherein said bosses have sloped faces to provide the snap-engagementwith the connection block.
 10. The arrangement as claimed in claim 1comprising stop projections on said cover for defining a fully insertedposition for the block in the cover.
 11. The arrangement as claimed inclaim 1 wherein said bosses are substantially centrally located on saidend walls.